Method of preventing shrinkage of wool



United States PatentO METHOD OF PREVENTING SHRINKAGE OF WOOL Firth L. Dennett, Midland, Mich., assignor to Dow Corning Corporation, Midland, Mich., a corporation of Michigan No Drawing. pplication April 20, 1953,

Serial No. 349,945

10 Claims. (Cl. 117-141) This application relates to a method of preventing shrinkage and felting of wool during laundering.

A perennial problem in connection with wool fabrics is the shrinkage and felting which these materials undergo when laundered. For example, a wool fabric will shrink as much as 30 per cent of its length after 5 or 6 washings and at the same time a large amount of felting takes place thereby destroying the desirable appearance of the fabric. Inasmuch as laundering is inherently cheaper and a more etlicient method of cleaning than dry cleaning, many attempts have been made to overcome this deficiency of wool fabrics. To date, none of these have been satisfactory.

One method which has been employed is that of chicrinating the wool. That is, the wool fiber is reacted with chlorine. This procedure seriously weakens the strength of the fabrics made therefrom and also imparts a harsh feel thereto. Another method is that of impregnating the wool with various organic resins such as, for example, melamine resins. This method also lowers the strength of the fabric and imparts a harsh feel thereto. A third method which has been attempted is that of treating the wool with various organosilicon compositions such as those described in U. S. Patent 2,588,365. Whereas these materials render wool water repellent they do not prevent the shrinkage or felting of Wool during laundering.

It is the object of this invention to provide a method for treating wool which will prevent objectionable shrinkage of the wool during laundering, which will prevent felting of the wool, and which does not change the appearance nor the hand of the fabric. It is a further object of this invention to provide a treatment which accomplishes the above objectives without lowering the strength of the wool fabric. Another object is to obviate the necessity of dry cleaning wool fabrics. Other objects and advantages will be apparent from the following description.

In accordance with this invention a wool fabric is treated with a composition composed essentially of (1) from 25 to 95 per cent by weight of a benzene soluble diorganopolysiloxane having a viscosity of at least 1 million cs. at 25 C., and (2) from 5 to 75 per cent by weight of an organosiloxane of the formula where R is an alkyl, alkenyl, or phenyl, n has an average value from 1 to 1.9, m has an average value from .1 to 1 and the sum of n+m has a value from 1.65 to 2.1.

The diorganopolysiloxanes (1) which are within the scope of this invention 'vary from materials having a viscosity of 1,000,000 cs. up to non-flowing benzene soluble materials. The higher molecular weight materials are preferred for the purpose of this invention. The organic radicals of the polysiloxane can be any alkyl or alkenyl radicals of less than 5 carbon atoms or a phenyl radical. It is preferred that at least per cent of the total number of organic radicals in the polysiloxane be of the lice above defined aliphatic radicals. Thus, specific examples of polysiloxanes which are operative are dimethylsiloxanc, diethylsiloxane, ethylmethylsiloxane, methylbutylsiloxane, methylpropylsiloxane, vinylmethylsiloxane, allylethylsiloxane, phenylmethylsiloxane, phenylethylsiloxane, and copolymers of any of the above. The diorganosiloxanes may also contain limited amounts of copolymerized diphenylsiloxane.

The organopolysiloxane (2) can be in several forms, all of which contain silicon bonded hydrogen atoms. For example, the siloxane may be a homopolymer of the formula RHSiO or it may be a copolymer of R'HSiO and/or HSiOi.5 with siloxanes of the formula R'sSiQs, R'zSiO and R'SiO1.5. It is to be understood that siloxane (2) can be any combination of such siloxanes, which combination has an R to Si and H to Si ratio within the above defined ranges. The viscosity of the siloxane component (2) is not critical; that is, it may vary, for example, from very fluid materials of 10 cs. up to nonflowing benzene soluble materials.

Specific examples of siloxanes (2) which are operative in this invention are ethylhydrogensiloxane, vinylhydrogensiloxane, allylhydrogensiloxane, stearylhydrogensiloxane, phenylhydrogensiloxane, and copolymers of methylhydrogensiloxane with up to 10 mol per cent tripropylsiloxane; copolymers of HSiO1.5 with dimethylsiloxane, dihexylsiloxane, vinylmethylsiloxane, phenylmethylsiloxane, and stearylmethylsiloxane; copolymers of methylhydrogensiloxane, dimethylsiloxane, monomethylsiloxane and monostearylsiloxane; and copolymers of butylhydrogensiloxane, HSiO1.5, triethylsiloxane and vinylphenylsiloxane.

The compositions employed in this invention, are prepared by mixing components (1) and (2) in any desired manner. The easiest way of doing this is to employ a mutual solvent such as benzene, toluene, xylene, or petroleum hydrocarbon solvents. The mixture may be applied to the fabric in any convenient manner such as by dipping or spraying. The materials may be applied in the form of a solution or as an aqueous emulsion. In all cases the concentration and time of treatment should be such that the fabric absorbs from .5 to 5 per cent by weight of the organopolysiloxanes. If less than this amount is picked up by the fabric, the beneficial results of this invention are not obtained. More than 5 per cent of the siloxane may be employed if desired; however, there is no advantage in doing so.

After treatment with the organopolysiloxane, the wool fabric is then heated at a temperature from -300" F. in order to dry the fabric and to set the siloxane therein. In general, heating about 10 minutes at 300 F. is sufficient.

The term wool fabric as employed herein includes any animal hair fabric such as, for example, sheep wool, mohair, cashmere, camel hair, alpaca wool, vicuna wool, llama wool, cow hair, and horsehair. The term wool includes fabrics which are 100 per cent animal hair and fabrics which are blends of animal hair together with cotton, polyacrolonitrile fibers, polyterephthalate ester fibers, polyamide fibers, rayon, or any other natural and synthetic fibers.

If desired, setting catalysts may be employed to haster. the cure of the siloxane. Suitable catalysts include, for example, the metal salts of carboxylic acids such as lead Z-ethylhexoate, lead naphthenate, carboxylic acids such as 2-ethylhexoic acid, and quaternary ammonium compounds such as trimethylbenzylammonium butoxide, trimethyl-Z-hydroxy-ethylammonium bicarbonate and trimethyl-2-hydroxyethylammonium Z-ethylhexoate. The catalysts is generally employed in amount less than 5 per cent by weight based on the total siloxanes.

Wool fabrics which have been treated in accordance with this invention do not undergo any change in appearance or hand. Furthermore the materials undergo less than 3 per cent shrinkage and show negligible felting after as many as 6 launderings in accordance with the Standard Test Mil-C-21-84 Test 4.3.1.2.3. This procedure was employed in all of the examples below and comprised placing the fabric in water at 140 F. in a standard reversing wheel washing machine. The water was added to the machine until it reached a level of 4 inches above the bottom of the inside cylinder. The water was maintained at that temperature and the machine was open ated for one hour. The fabric was then removed and centrifuged in a 20 inch diameter extractor for 5 minutes at a speed of 1750 R. P. M. and thereafter dried in a tumbler dryer at a stack temperature of 130 F. for 30 minutes. The fabric was then removed from the dryer. sprinkled with water, allowed to stand for 5 minutes, and pressed in a fiat-bed press until it was dry. The fabric was then measured to the nearest 16th of an inch in order to ascertain the shrinkage.

The following examples are illustrative and are not to be construed as limiting the intention which is properly delineated in the appended claims.

EXAMPLE 1 The organopolysiloxane employed in this example was a mixture of siloxanes (1) and (2) in the varying proportions shown in Table I below. Organosiloxane (1) was a benzene soluble non-flowing dimethylpolysiloxane. Organosiloxane (2) was a copolymer of 98 mol per cent methylhydr'ogen'polysiloxane and 2 mol per cent trimethylsiloxane. The copolymer had a viscosity of about 30 cs. at 25 C.

The shrinkage figures shown in Table I represent an average of 6 measurements.

In each run shown in the table, a sample of 10.5 oz. olive drab wool fabric was dipped into a 2 per cent xylene solution of the organosilicon compounds and thereafter was squeezed free of excess solvent and air dried. Each sample was then heated 10 minutes at 300 F. In each case, the siloxane solution contained the catalyst lead Z-ethylhexoate in amount of 2 per cent by weight lead, based upon the total weight of siloxanes (1) and (2).

ing fabric thereafter heated as shown in that example. The fabric contained 1.4 per cent by weight of the polysiloxanes and was found to have the following shrinkage upon laundering.

The initial spray rating of the treated wool before laundering was 100 per cent.

EXAMPLE 3 Results equivalent to those of Example 1 are obtained when a composition comprising a mixture of per cent by weight of a benzene soluble non-flowing ethylmethylpolysilox'ane and 25 per cent by weight of a benzene soluble ethylhydrogen polysiloxane is applied to a wool fabric in accordance with the method of Example 1.

EXAMPLE 4 Equivalent results are obtained when per cent by weight of a benzene soluble non-flowing copolymer having the composition mol per cent vinylrnethylpolysiloxane and 10 mol per cent phenylbutylpolysiloxane is mixed with 15 per cent by weight of a copolymer having the composition 88 mol per cent vinylhydrogensiloxarre, .10 mol per cent phenylhydrogensiloxane and 2 mol per cent monostearylsiloxane and applied to a wool fabric in the manner of Example 1.

That which is claimed is:

l. A method of treating wool fabrics to prevent the shrinkage thereof during washing which comprises treat ing the fabric with at least .5% by weight based on the weight of the fabric of a composition composed essentially of (1) from 25 to per cent by weight of a benzene soluble diorganopolysiloxane having a viscosity of at least 1,000,000 cs. at 25 C., in which siloxane the organic radicals are selected from the group Table I Percent Shrinkage After Each Washing I Percent by Wt. lptal Organosiloxane Percent Shrinkage by Wt. I I1 III IV V VI Pick up 1) (2) W F W F W F W F W F W F W F 11. 7 s. 1 7. 2 a. 0 s. s s. 3 3. 9 4. 0 v 5. t 3. 7 2. 0 '3. 5 37 p e 90 10 1.4 1.0 0.9 .8 4 .1 -.2 .7 1.1 .2 .3 2 -.7 1.8 75 25 1.4 1.7 1.0 .3 -.3 .5 1.3 3 .i .4 2 -.9 .d 2.3 5O 50 1.4 3.0 2.0 0 .2 O .1 3 2.5 25 75 1.4 1.6 2.3 .6 0 .5 .S 2.7 3.1 40 60 1.4 6.0 3.5 5.8 5.3 6.6 6.1 5 5 2 -3.0 20.1

NOTE .A minus sign indicates that there was elongation rather than shrinkage. In this run the dirncthylpolysiloxanc (1) had a viscosity of 10,000 cs. at 25 C. This run 18 included tor comparison.

W= a will All of the above treated samples had a spray rating from 90 to prior to laundering and a spray rating of 80 after 3 launderings.

EXAMPLE 2 The polysiloxane employed in this example was a mixture of 75 per cent by weight of a benzene soluble nonfiowing dimethylpolysiloxane and 25 per cent by weight of a copolymeric siloxane having the composition 75 mol per cent dimethylsiloxane and 25 mol per cent HSiO1.5. The mixture was dissolved in xylene to give a 2 per cent by weight solution of the total siloxanes. Lead Z-ethylhexoate was added in amount sufficient to give 2 per cent by weight lead metal based on the total siloxanes. A sample of the Wool fabric of Example 1 was treated with this solution in the manner of Example 1 and the resultconsisting of alkyl and alkenyl radicals of less than 5 carbon atoms, and phenyl radicals, at least 50 per cent of the total number of radicals being the defined aliphatic radicals and (2) from 5 to 75 per cent by weight of a benzene soluble siloxanc of the formula a'nsifim r i i 3. A method of treating wool fabrics to prevent shrinkage of a fabric during washing which comprises treating the fabric with at least .5% by weight based on the weight of the fabric of a composition composed essentially of from 25 to 95 per cent by weight of a benzene soluble dimethylpolysiloxane having a viscosity of at least 1,000,000 cs. at 25 C. and from to 75 per cent by weight of a benzene soluble methylhydrogenpolysiloxane and thereafter heating the treated fabric at a temperature from 100-300 F. until the siloxane is cured.

4. A method of treating wool fabrics to prevent the shrinkage thereof during washing which comprises treating the fabric with at least .5% by weight based on the weight of the fabric of a composition composed essentially of (1) from 25 to 95 per cent by weight of a benzene soluble diorganopolysiloxane having a viscosity of at least 1,000,000 cs. at 25 C., in which siloxane the organic radicals are selected from the group consisting of alkyl and alkenyl radicals of less than 5 carbon atoms, and phenyl radicals, at least 50 per cent of the total number of radicals being the defined aliphatic radicals and (2) from 5 to 75 per cent by weight of a benzene soluble siloxane of the formula where R is selected from the group consisting of alkyl, alkenyl and phenyl radicals, n has an average value of from 1 to 1.9, m has an average value from .1 to 1 and the sum of n-l-m has a value from 1.65 to 2.1, and (3) a catalyst and thereafter heating the treated fabric at a temperature from 100 to 300 F. until the siloxane is cured.

5. The method in accordance with claim 4 wherein siloxane (1) is a dimethylpolysiloxane and siloxane (2) is a methylhydrogenpolysiloxane.

6. A method in accordance with claim 4 wherein siloxane (2) is an ethylhydrogenpolysiloxane.

7. A non-shrinking, noniclting wool farbic containing from .5 to 5 per cent by Weight of a cured organosilicon composition composed essentially of from 25 to 95 per cent by weight of a benzene soluble diorganopolysiloxane having a viscosity of at least 1,000,000 cs. at 25 C., in which siloxane the organic radicals are selected from the group consisting of alkyl, and alkenyl radicals of less than 5 carbon atoms and phenyl radicals, at least per cent of the total number of organic radicals being the defined aliphatic radicals and (2) from 5 to per cent by weight of a benzene soluble siloxane of the formula where R is selected from the group consisting of alkyl, alkenyl and phenyl radicals, n has an average value of from 1 to 1.9, m has an average value from .1 to l and the sum of n+m has a value from 1.65 to 2.1.

8. A wool fabric in accordance with claim 4 in which siloxane (1) is a dimethylpolysiloxane and siloxane (2) is a methylhydrogenpolysiloxane.

9. A wool fabric in accordance with claim 7 wherein siloxane (2) is an ethylhydrogenpolysiloxane.

10. A method in accordance with claim 1 in which siloxane (2) is a methylhydrogenpolysiloxane.

References Cited in the file of this patent UNITED STATES PATENTS 2,608,495 Barry Aug. 26, 1952 2,612,482 Rasmussen Sept. 30, 1952 2,615,824 Minor et a1 Oct. 28, 1952 2,643,375 Gant June 23, 1953 

1. A METHOD OF TREATING WOOL FABRICS TO PREVENT THE SHRINKAGE THEREOF DURING WASHING WHICH COMPRISES TREATING THE FABRIC WITH AT LEAST .5% BY WEIGHT BASED ON THE WEIGHT OF THE FABRIC OF A COMPOSITION COMPOSED ESSENTIALLY OF (1) FROM 25 TO 95 PER CENT BY WEIGHT OF A BENZENE SOLUBLE DIORGANOPOLYSILOXANE HAVING A VISCOSITY OF A LEAST 1,000,000 CS. AT 25* C., IN WHICH SILOXANE THE ORGANIC RADICALS ARE SELECTED FROM THE GROUP CONSISTING OF ALKYL AND ALKENYL RADICALS OF LESS THAN 5 CARBON ATOMS, AND PHENYL RADICALS, AT LEAST 50 PER CENT OF THE TOTAL NUMBER OF RADICALS BEING THE DEFINED ALIPHATIC RADICALS AND (2) FROM 5 TO 75 PER CENT BY WEIGHT OF A BENZENE SOLUBLE SILOXANE OF THE FORMULA 